Hydraulic power unit



y my 1951 A. F. HABENICHT 25%,285

HYDRAULIC POWER UNIT Filed July 15, 1948 2 Sheets-Sheet l 3 1Q, 19511 A. F. HABENICHT 295,235

HYDRAULIC POWER UNIT Filed July 15, 1948 2 Sheets-Sheet 2 Patented July 10, 1951 UNITED STATES PATENT OFFICE HYDRAULIC POWER UNIT August F. Habenicht, Tinley Park, Ill.

Application July 15, 1948, Serial No. 38,812

4 Claims. 1

This invention relates to hydraulic power devices, and in particular to a reciprocating-piston hydraulic engine adapted. to operate a deep-well pump or other load having great inertia.

In the design of power means for starting and reciprocating the shafts of deep-well pumps the inertia of the pump shaft and its associated piston presents a'very serious difficulty. A typical deep-well pump may have a shaft several hundred feet or more in length, with a piston at the lower end thereof. The overall weight of the shaft and piston may be very great, and starting it upward against the force of gravity can, in general, be accomplished only by the application of a relatively tremendous thrust. If the power plant at the top of the well is made large enough to provide the required initial thrust without overloading, then its capacity is largely unused throughout the major part of the stroke, since the thrust required for raising the shaft after it is once in motion is very much less than the thrust required to start it. On the other hand, if a power plant be provided whose steady out-put is appropriate for the movement of the shaft, then it is likely to be overloaded to the breaking point when the pump shaft is started upward.

An object of this invention is tot provide a hydraulic power unit having means adapted to re-v V ceive energy during the power cycle and to store it for use in assisting the power unit during that portion of the cycle when a heavy mass must be started in motion. Another object of this invention is to provide a hydraulic power unit having a cushion chamber into which hydraulic fluid can pass and store energy by compressing the air therein, such stored energy being made available for the assistance of the power unit during the portion of its stroke wherein abnormally great thrust is required.

Still another object of this invention is to provide, in a hydraulic power unit having a cushion chamber for the storage of energy by air compression, a novel means for insuring that the air content of the chamber is held at an adequate level to insure proper operation. A further ob ject of this invention is tov provide, in such a hydraulic power unit, means insuring that the energy stored in the cushion chamber is released, at the proper time and in the proper magnitude, to assist the power unit in starting a load having great inertia. Other specific objects and advantages will appear as the specification proceeds.

Theinvention is illustrated, in a preferred embodiment, by the accompanying drawings, of

which Figure 1. is a view in front elevation f a per side of box 22.

hydraulic power unit made according to this invention; th figure is partly in section, and connecting pipes and certain other components are represented diagrammatically. Fig. 2 is a vertical view, partly in section, taken along the line 22 in Fig. 1; and Fig. 3 is a horizontal sectional view of the power unit, taken along the line 3-3 of Fig. 2.

In the illustrations, a hollow rectangular box or chamber 22 is supported in a horizontal position by any suitable means (not shown). A pair of hydraulic power cylinders H pass through and are rigidly affixed, as by welding, to box 22 near one end thereof; a corresponding pair of power cylinders H are carried by box 22 near its opposite end, as best shown in Fig. 3. A pair of ports 28 in the sides of each of the cylinders H and H communicate with the interior of box 22. Each of the power cylinders H carries a piston I9 and a piston rod [8; at their upper ends piston rods l8 are affixed to a yoke Y. Each of power cylinders H has a piston l-9a and a piston rod l8a; piston rods l8a are affixed at their upper ends to a yoke Y.

Each of the cylinders H and H is equipped at its upper end with a stuffing box, comprising an annular internal shoulder 2| formed integrally with or welded into the cylinder, packing material 21 positioned around the piston rod and seated on shoulder 2|, a gland 26 adapted to compress packing material 21, and a cap 25 threaded onto the top of the cylinder and adapted to force gland 26 downward to compress packing mate.- rial 27. Annular shoulder 2|, gland 26, and cap 25 all have central apertures machined to provide a snug sliding fit with the piston rod I8 or [8a.

A shaft P, which may be the shaft of a deepwell :pump, passes through aperture 20 in box 22 and is affixed to yoke Y at a point midway between piston rods l8. Aperture 20 is sufficiently large to provide ample clearance for shaft P, and the annular wall of aperture 20 is integrally formed with or welded to the top and bottom of box 22.

The bottom of each of the cylinders H is fitted tightly into and welded respectively to one of a pair of closed tanks 29; tanks 29 are connected together by a communicating pipe 30. Similarly, the bottom of each of the cylinders H is fitted into a tank 29a, the tanks 29a being connected together :by a communicating pipe 30a.

A pair of upright supporting arms or standards HI and II are affixed, as by welding, to the up- Arms l0 and II carry at their tops journal bearings 12 and [-3 respecby yieldable couplings comprising bolts Nuts 34 are adjusted 3 tively; journaled into said bearings is an axle l6. At its opposite ends axle l6 carries a pair of sprocket wheels S. Chains C pass over wheels S and connect yoke Y to yoke Y. Chains C are secured to yoke Y by bolts 3|a and to yoke Y 3| and coil springs 32. Springs 32 operate to maintain at all times a slight tension on chains C.

Journal bearings |4 and I5 are welded, or otherwise affixed, to the lower side of boX 22; journaled therein is an axle carrying at its opposite ends sprocket wheels S. Chains C pass around wheels S and connect yoke Y to yoke Y, chains C' being secured to yokes Y and Y by suitable bolts 33 and cooperating nuts 34. to maintain chains C under slight tension.

Control valve 46 is mounted vertically in rigid relationship to cylinders H and H by any suitable means (not shown). Valve 40 includes an upper section containing a cylinder 4| and a twosection piston 48 slidable therein. A piston rod 42 is afiixed to the upper end of piston 48; it extends above valve 46 to a level slightly higher than the highest point attained by yoke Y when pistons l9 are at the top of their stroke in power cylinders I-I. Piston rod 42 passes slidably through apertures 43 in the arm 35 which extends laterally from yoke Y. Flange members 44 and 46 are affixed rigidly to rod 42. Member 44 is positioned near the top of piston rod 42, where it is engaged by arm 35 when pistons l9 reach the topmost portion of their stroke, such engagement causing piston 48 to rise to its upper position as shown in the drawing. Flange member 46 is positioned on rod 42 at a point near the level reached by yoke Y when pistons |9 are at the lowest portion of their stroke, member 46 being engaged by arm 35 and piston 46 moved thereby to its lower position at the time pistons l9 attain the lowest portion of their stroke. Coil spring 45 is afllxed to flange member 44 and extends downward therebelow around rod 42; coil spring 41 is affixed to member 46 and surrounds rod 42 thereabove.

The lower part of valve 46 comprises a cylinder 49 and a four-section piston 50 reciprocable therein. The upper and lower parts of valve 49 are separated by a bulkhead 5| containing a passage 86 which connects the upper end of cylinder 49 with a port on the side of cylinder 4| near the lower end thereof.

Valve I00, mounted on the structure of the hydraulic power unit by any suitable means, comprises cylinder |0| and a four-section piston I62 reciprocable therein.

A hydraulically-actuated adjustable valve 52 comprises a valve cylinder 56, a sliding valve member 55 machined to fit snugly within cylinder .56, a hydraulic cylinder 53, and a piston 54 slidable within cylinder 53 and carried by the lower end of valve member 55. An adjustable thumb-screw 51 is threaded through the top of the housing of valve 52 and is positioned to engage the upper end of valve member 55, so that its position of maximum upward movement may be varied by turning thumb-screw 51.

Hydraulically-actuated valve 58 comprises a valve cylinder 62 having a valve seat 68 centered at the lower end thereof, a slidable valve member 6| positioned within cylinder 62, a hydraulic cylinder 59, and a piston 60 slidable within cylinder 59 and carried by the of valve member 6|.

Compression chamber 69 is a closed, air-tight upper end tank having a baflle plate 10 mounted on the floor thereof. Hydraulically-actuated valve 64 is similar in structure to valve 58; it comprises hydraulic cylinder 65, piston 66 reciprocable therein, valve member I29, valve cylinder IZI, and valve seat 61.

Hydraulically-actuated air pump H comprises a pump chamber 15, a pump piston 14 recipro cable therein, a power cylinder 12, a piston 13, carried by the upper end of pump piston 14 and reciprocable in cylinder 12, a ball-check valve 16 connecting the interior of cylinder 15 to atmosphere, and a ball-check valve 1! connecting the interior of cylinder 15 to pipe 18, which in turn communicates with the interior of compression cylinder 69. Ball-check valve 16 is spring-biased so as to permit flow of air, under pressure differential, from the atmosphere to the interior of cylinder 15 but to prevent any flow in the opposite direction. Ball-check valve 11 is spring-biased to permit flow of air under pressure from cylinder 15 into pipe '16 but to prevent any flow of gas in the opposite direction.

Hydraulic pressure for the operation of the power cylinders and other hydraulically-actuated devices is provided by pumps and 8|, which are indicated diagrammatically on the drawing. These may be conventional rotary hydraulic fluid pumps, driven by an electric motor or any other suitable source of energy, capable of generating hydraulic pressures of considerable magnitude. In a typical deep-well pump installation, the pressures required of pumps 86 and 8| might be of the order of 700 to 800 pounds per square inch.

Tank 82, which has a conventional air vent 83, is represented diagrammatically on the drawing; it may be any suitable storage tank for hydraulic fluid. The hydraulic fluid employed in the operation of this invention may be any stable liquid; I prefer to use a light oil.

Pipe '84 and its branch 84a connect tank 82 to pumps 8| and 86 respectively; the direction of flow of liquid in pumps 80 and BI is as indicated by arrows on the drawing.

From pump 80 pipe carries fluid to a port located midway up the wall of cylinder 4| and through branch pipe 85a to a port midway up 'the wall of cylinder 49. Pipe 90 connects a port near the upper end of cylinder 4| to a port at the bottom of cylinder 49. Pipe 9| connects a port on the wall of cylinder 49 about one-third of the distance up from the bottom thereof, to a port in valve 52 opening into chamber 56. A branch pipe 9|a connects pipe 9| to the upper end of hydraulic power cylinder 53 in valve 52. Another port communicating with valve cylinder 56 is connected by pipe 9|b to one of the tanks 29. Pipe 92 connects a port on the Wall of cylinder 49, about two-thirds of the distance up from the bottom thereof, to one of the tanks 29a. Pipe 98 connects tank 82 to a port near the top of cylinder |9| in valve I60; branch pipe 98a connects pipe 98 to a port near the bottom of cylinder |6|; branch pipe 981) connects pipe 98, through spring-biased safety valve 63, to a port in the side of valve cylinder |2| in valve 64. Branch pipe 980 connects a port near the bottom of cylinder 49 with pipe 98b; branch pipe 98d connects a port at the top of cylinder 4| to pipe 980; branch pipe 98c connects a port near the top of cylinder 49 to pipe 98d; and branch pipe 98) connects the bottom of cylinder 4| with pipe 98d.

Pipe ,95 connects .a port near the top of cylinamazon inder 4I.

Pipe 91 connects pump 8| to a port midway 1:

up the side of cylinder IOI; a spring-biased safety valve I05, similar in structure to valve 63, is indicated diagrammatically on the drawing as connected between pipes 91 and 9%. This valve may be adjusted to permit liquid to pass from pipe 9! into pipe 98b and thence back to tank 82 at a predetermined pressure, the magnitude of which may vary according to the particular application. The functional result of valve I05 is to maintain a constant source of pressure for the actuation of the various power cylinders operated by pump 8| in practice, this constant pressure might be of the order of 500 pounds per square inch.

Pipe I03 connects a port on the side of cylinder IOI about two-thirds of the distance up from the bottom thereof, to the lower end of hydraulic cylinder I2, in compressor pump II. Branch pipe I03a connects pipe I03 to a port at the lower end of hydraulic cylinder 59 in Valve 58. Branch pipes I03b connects pipe I03a with a port at the top of hydraulic power cylinder 65 in valve Pipe I04 connects a port on the side of cylinder IOI, about one-third of the distance up from the bottom thereof, to a port at the top of hydraulic cylinder l2 in compression pump H. Branch pipe i04a connects pipe I04 to a port at the top of power cylinder 59 in valve 58. Branch pipe I04b connects pipe I04a to a port near the bottom of power cylinder 53 in valve 52. Branch pipe I040 connects pipe I04 to a port on the bottom of power cylinder 65 in valve 94. Pipe 96 connects a port on the under side of rectangular box 22 to pipe 98.

A pipe I95 provides communication between one of the tanks 29 and valve seat 68 in valve 58; pipe I01 runs from a port opening into cylinder 62 of valve 53 to a port opening into the lower end of compression chamber 69. Pipe I9 connects a port on the side of chamber 69, about one-fourth of the distance up from the bottom thereof, to valve seat 91 in valve 64.

Operation The drawing shows the hydraulic power unit of the invention at that point in its operation wherein pistons I9 have just completed their upward stroke and are ready to start downward. As yoke Y reached its maximum upward displacement, arm 35 engaged spring 45 and caused piston 48 to move to its upward position as shown. Thereupon liquid under pressure from pump 80 flowed from pipe 85 through pipe 90 to the lower end of cylinder 49 and caused piston '50 to rise to its upward position, as shown. At the same time, liquid under pressure from pump 80 flowed frompipe 85 through cylinder 4| and pipe 95 to the upper end of cylinder IOI, causing piston I02 to assume its lower position, as shown.

At the stage of operation illustrated in the drawings, liquid under pressure is flowing from pump 80 through pipes 85 and 85a, cylinder 49, and pipe 92 into tank 29a, and as pressure is built up in the tanks 29a pistons I90; will rise,

carrying with them yoke Y.

As pistons I9a begin to rise, pistons I9, in hydraulic cylinders H, will start to drop and yoke Y will be lowered, carrying with it shaft P.

Shaft P, as has been pointed out, will normally be carrying a very heavy mass, and as a result '9I' to valve 52.

is most important that it be prevented from dropping precipitately and thereby damaging the 'deep well pump or other device associated with it. Before describing in detail the means whereby rapid descent of shaft P is prevented, however, actions resulting from the shiftin position of piston I 02 wiil bexdescribed.

When piston I92 is moved to its lowered position, as :shown, liquid under pressure from pump "9| flows through pipe 91 and pipe I04 and its various branches, resulting in the raising of valve member 55 in valve 52, the closing of valve 58, the opening of valve 64, and the lowering of piston 14 in compression pump 1 I. As the various pistons '60, 96, and 1'3 are caused to shift position, the hydraulic fluid thereby vented from the respective power cylinders is free to flow through pipe I03 and its various branches back to cylinder I01 and thence through pipe 98' to storage tank 82. As piston 54 is raised by pressure from fluid introduced through pipe I 942), the liquid above piston 54 is vented through pipe 9Ia, pipe 9|, cylinder '49, and pipe 990 back to tank 82-.

Now, to return to the operation of power cylin'- 'ders H, it will be seen that as yoke Y is lowered, the hydraulic fluid in power cylinders H will be forced out of tanks 29 through pipe 9Ib, valve cylinder 56, pipe 9|, cylinder 49, and pipe 980 back to tank 92. The rate of flow of this liquid can be controlled by appropriate adjustment of thumb-screw 5! so as to permit shaft P to be lowered at any desired rate. In this stage of the power units operation, none of the fluid in power cylinder H can flow into compress-ion tank 99, since val-ve58 is closed.

While pistons I9 are completing their downward movement, compressor pump II compresses the air in cylinder I5 and, when piston I4 reaches the bottom of its stroke, compressor pump "II injects, by Way of ball-check valve H and pipe I8, 'a' charge of compressed air into tank 69.

When pistons I9 in power cylinders H reach the bottom of their stroke, arm engages spring 4! and causes piston 48 to shift to its lower position. Thereupon, fluid under pressure from pump '80 flows through pipe 85, cylinder 4|, and passage '86 into the top of cylinder 49, causing piston to' assume its lower position. At the same time, liquid flows from cylinder 4| through pipe 94 into thelower end of cylinder IIlI, causing piston I02 to assume its upper position. The liquid displaced "by the movement of pistons 48, 59, and I 02 is free piston in valve 58, piston 69 in valve 64, and

piston I3 in compressor pump II. At the same time, liquid under pressure from pump flows through pipe 85, pipe 95a, cylinder 49, and pipe The fluid from pump 80 flows down pipe 9Ia, and causes piston 54 to be lowered, thereby opening valve 52 and permitting free passage of liquid from pipe 9| into tanks 29. The liquid displaced by the shift in position of pistons 54, 60", 66, and I3 can flow back to tank 82 by way of pipe I04 and its various branches, the lower portion of cylinder IOI, pipe 98a, and pipe 98.

When liquid from pump 80 begins to flow into the tanks 29 it imposes a hydraulic pressure on pistons I9, tending to force them upward and accordingly to raise pump shaft P. When the power unit is first placed in operation, the initial pressure on pistons l9 will be insuflicient to overcome the inertia of shaft P, and but for the cushion chamber feature of this invention, a move-or-break situation would be created wherein pump 80 would be severely overloaded and probably stalled or broken. In this invention, however, no such result can occur; the hydraulic fluid pumped into tank 29 by pump 80 can flow through pipes I06 and I01, past the now-open valve 58, into compression chamber 69. As the hydraulic fluid rises in chamber 69 it compresses the air therein before it and produces an increasing pressure in the upper end of tank 69. This flow, and consequent compression, continues until the pressure in tank 29 is great enough to overcome the inertia of pump shaft P to cause it to start upward. Thereupon, the further advance of hydraulic fluid into power cylinders H is assisted by the compressed air in the top of tank 69, and as pistons [9 rise to the top of their stroke, some of the oil in tank 69 is discharged through pipes I01 and I06 into tanks 29 and cylinders H.

After the pump has been in operation for several cycles, a state of equilibrium is reached whereby the pressure remaining in tank 69 between successive up-strokes of pistons I9 is approximately equal to the pressure necessary to raise pump shaft P after its inertia has been overcome. As pistons l9 reach the upper limit of their stroke, arm 35 again engages spring 45 and causes the valves to re-assume the positions shown in the drawing. Thereupon, valve 52 closes, so as to afford only a restricted passage for the outflow of liquid from cylinders H back to tank 82, as is required to prevent precipitate lowerin of shaft P. Valve 58 closes and thereby stores within tank 69 the potential energy represented by the air compressed therein. Valve 64 opens, and compression pump 13, which during the previous half-cycle has charged cylinder 15 with air from the atmosphere through valve 16, now compresses it and forces it under pressure into tank 69.

The functions and purposes of compressor pump H, baflie plate 10, and valve 64 are related to the maintenance of smooth, dependable operation of compression tank 69. As will be understood from the foregoing descriptions, it is desirable that tank 69 provide, at each time the pistons l9 begin an up-stroke, a substantial supply of hydraulic pressure to supplement and assist pump 80 in its task of overcoming the inertia of shaft P and starting it on its upward course. It

has been found that, if tank 69 is employed alone, in course of time the air originally trapped in the upper portion of the tank becomes mixed with the hydraulic fluid and passed off to tank 82,- where it escapes to the atmosphere through vent 83. As the air is thus removed from tank 69, its effectiveness as a cushion is reduced. This condition can be considerably lessened by the use of baflle plate 16, which minimizes the turbulence of the hydraulic fluid within tank 69 and thus reduces the tendency of the fluid to absorb air. Nonetheless, a certain amount of air escapes from tank 69 despite the action of bafile plate 10, and if the power unit is to be employed for a long period of continuous operation a means must be provided for restoring air to tank 69 during operation. Compressor pump ll performs that function.

Compressor pump H valve 64, and safety valve 63 cooperate to maintain the air and liquid content of tank '69 within the upper and lower limits required for efficient performance of its function. During the up-strokes of pistons l9, valve 64 is closed and the liquid level in tank 69 is free to rise as far as may be necessary to build up the hydraulic pressure required to start and raise pump shaft P. During the downstrokes of pistons l9, valve 64 is opened and any excess of pressure which may have been built up in tank. 69 is relieved through safety valve 63. Valve 63 should be set to pass fluid at a pressure slightly below that required within power cylinders H to raise shaft P. For example, should a pressure of 500 pounds per square inch within cylinders H be required to raise shaft P after it has been started, valve 63 should be set to pass fluid at a pressure of about 490 pounds per square inch. Then, at the beginning of each upstroke of pistons 19, the pump 86 will build up within tank 29 and tank 69 a pressure sufiicient to start shaft P; thereafter, during the remainder. of the up-stroke of pistons [9, liquid will flow out of tank 69 and into power cylinders H until the pressure within tank 69 has dropped to 500 pounds per square inch. When this point has been reached, the pressure in tank 69 will remain substantially constant until pistons l9 complete their up-stroke. During this portion of the cycle valve 64 is closed and valve 63 is thus out of the circuit. When the down-stroke of pistons 19 commences, compressor pump H injects a charge of compressed air into tank 69, valve 58 closes, and valve 64 opens. After the charge of air from compressor pump ll is discharged into tank 69, any excess fluid pressure over 490 pounds per square inch is relieved by discharge of fluid through valve 63 back to storage tank 82. If the air provided by compressor pump ll is greater than that required to replace the air lost by absorption in the hydraulic fluid, the liquid level in tank Tl will gradually drop until it reaches the port communicating with pipe 19. It cannot drop below that level, however, since excess air thereafter' provided by compressor pump II will be vented directly through valve 63. The net result of the combined action of compressor pump ll, valve 64, and valve 63 is thus to maintain the air and liquid contents of tank 66 always within limits which will give good performance.

The ports 28, the interior of box 22, and pipe 96 connecting box 22 to storage tank 82 provide the important advantage in this invention of maintaining atmospheric pressure on both sides of the stufling box at the upper ends of power cylinders H andH, since any leakage of hydraulic fluid past pistons l9 and [9a is simply returned to tank 82, and can never build up a hydraulic pressure on the stuffing box. This feature, which is of very great importance is providing dependable and trouble-free operation, is disclosed and claimed in my earlier co-pending application, Serial No. 35,100, entitled Fluid Pump, filed June 25, 1948.

In the drawing, for illustrative purposes, power cylindersl-I and H have been shown as having equal cross-sectional areas. In many instances it may be preferable to make power cylinders H larger in cross-sectional area than power cylinders H. Any desired proportions may be adopted for these power cylinders without affecting the sequence of operations, since the valve actions in this invention are controlled solely by the position of yoke Y.

While a particular embodiment of the invention has been shown and described in this specification in considerable detail for purposes of illustration, it will be understood that the struc- 9 tural details may be varied widely by those skilled in the art without departing from the spirit of my invention.

I claim: 1. In a hydraulic engine adapted to move in vertical reciprocating motion a load having substantial mass, a power cylinder, a piston reciprocable therein, inlet means for introducing hydraulic fluid into the cylinder comprising a valve having an open position and a closed position, said valve when in the closed position providing a restricted passage for the flow of fluid, a closed chamber communicating with the cylinder adapted to receive hydraulic fluid until the pressure on said fluid exerted by the gas in the chamber is suificient to start the piston, and control means automatically responsive to the movement of the piston operative to open the valve when the load is to be moved against the force of gravity and to close the same when the load is being moved in a direction wherein its motion is aided by the pull of gravity.

2. In a hydraulic engine adapted to move in vertical reciprocating motion a load having substantial mass, a power cylinder, a piston reolpro- 10 load is to be moved against the force of gravity and to close both valves when the load is being moved in a direction wherein movement is aided by the pull of gravity.

3. Apparatus according to claim 1 wherein a hydraulically actuated air pump is connected to the closed chamber and operative, responsively to the control means, to inject a quantity of gas into the closed chamber during each cycle of piston movement.

4. Apparatus according to claim 2 wherein a hydraulically actuated air pump is connected to the closed chamber and operative, responsively to the control means, to inject a quantity of gas into the closed chamber during each cycle of piston movement.

AUGUST F. HABENICHT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 780,614 Nash Jan. 24, 1905 1,087,883 Loomis Feb. 17, 1914 1,480,257 Gerlinger Jan. 8, 1924 1,596,145 Black Aug. 17, 1926 2,072,595 Hutchison Mar. 2, 1937 2,141,703 Bays Dec. 27, 1938 2,170,890 Allen Aug. 29, 1939 2,232,977 Mast May 12, 1942 2,347,302 Twyman Apr. 25, 1944 2,414,979 Ross Jan. 28, 1947 

